This project addresses the RFA's goal of examining "the usefulness of mental health screening instruments" for children and adolescents. We focus on the validity of screens because they are much more widely used in the real world than are full psychiatric interviews (e.g., in schools, primary care clinics, and population surveys), and because little work has been done to validate them, despite their promise for early identification and prevention. This application has two phases. The aims of Phase 1 are to assemble and analyze a representative collection of data sets relevant to the validity of screens for child psychiatric disorder. Here validity is interpreted as screening efficiency relative to a structured psychiatric interview. Using statistical methods developed for cancer research where there is no agreed gold standard for diagnosis, we will construct a multi-screen/multi-interview matrix that will provide measures of the efficiency of a range of screens, relative to one or more interviews, in various settings (epidemiologic, primary care, school, clinic, juvenile justice, etc.), and where possible by age, sex, race/ethnicity, and diagnosis. The advantages of this approach are quick access to several informative data sets. Disadvantages are that many of the "criterion" measures are now out-of-date or were inadequate as indicators of validity. Phase 2 of this program of work will begin the task of rigorously testing the most promising screens, in relation to 3 state-of-the-art diagnostic interviews (Diagnostic Interview Schedule for Children (DISC-IV), Child and Adolescent Psychiatric Assessment (CAPA), Developmental and Well-Being Assessment (DAWBA)). We propose to begin this work (which must be done separately in each type of setting where screens are used) using a primary care sample, for reasons of public health importance, generalizability, and cost. Youth aged between 9 and 16 (N=1200) will be recruited from a large pediatric primary care clinic. There will be 8 cells of 150 each, counterbalanced by sex, White/African American race/ethnicity, and age (9-12, 13-16). Participants (parent and child) will complete the chosen set of screening measures twice. Each screening will be followed by a different psychiatric interview. Each participant will receive 2 of 3 interviews; 400 will thus receive each combination. Screening efficiency will be calculated relative to each interview separately, and averaged over all 3.